Nyet, spasibo: tempting they might look, but Russian authorities have drawn a line over New Zealand beef livers until contamination issues are cleared up.

Russia has followed through with its threat to temporarily ban New Zealand beef products because they have been allegedly contaminated.

New Zealand officials are "engaging" with their counterparts in Russia to unravel what is behind the ban, slapped on exports on Monday.

Last week Russia's agriculture safety watchdog claimed to have found the feed additive ractopamine in some samples, but New Zealand politicians and officials have pointed out that the substance is prohibited in beef and sheepmeat, and has never been detected in New Zealand products.